The aim of the current study is to experimentally test two implementation models for achieving treatment fidelity and positive child and parent outcomes in the delivery of the Incredible Years (IY) parent program. Ultimately, effective implementation of an EBP intervention, such as IY, in community mental health settings depends upon therapists learning the new program and delivering it with adherence to the content and competence in the therapeutic methods and processes. Even for well documented interventions, such as the IY, which has strong material support and a long history of providing complementary training workshops, effective implementation may require more intensive efforts to support high fidelity implementation. Improving understanding of factors that influence effective implementation and fidelity to evidence-based practices (EBP) is an important national health care priority. This randomized, controlled trial will compare two models for implementing the Incredible Years treatment program with a usual care control condition. Organizations delivering the program under the Standardized Implementation Model (SIM) will receive detailed materials supporting the Incredible Years and will participate in one-time intensive training. The Enhanced Implementation Model (EIM) includes all elements of SIM plus initial organizational support, promotion of values fit between therapist and organization, and ongoing training, technical support and consultation for therapists and agency supervisors. This study will test these two IY implementation models in a sample of 720 children with conduct problems whose families are receiving Temporary Assistance for Needy Families (TANF) in California. Two-thirds of families selected for the study will be randomly assigned to participate in the Incredible Years parenting program, which will be paid for by Medicaid, while one-third of families will be followed naturalistically with no changes made to the normal services they receive through TANF (CONTROL). Among families participating in the Incredible Years conditions, half will receive these services from therapists in an agency randomized to implement the practice under the SIM. The other half will receive services from therapists in an agency randomized to implement under the EIM. Parent and child outcomes under the two-implementation models will be assessed as well as therapist implementation fidelity under each condition.